<!DOCTYPE html>
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<meta charset="utf-8"> 
 <title>菜鸟教程(runoob.com)</title> 
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      <script>
        document.onclick = function(e){
            var r = 50;  //圆的半径
            var x1 = 100,  y1 = 100;  
            var x2 = e.clientX,
                y2 = e.clientY;
            var len=Math.abs(Math.sqrt(Math.pow(x2-x1,2)+Math.pow(y2-y1,2)));  
            if(len<=50){
                console.log("Inner");
            }else{
                console.log("Outer");
            }
        }
    </script>

</body>
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